The present invention relates to a structure of an automatic transmission and more particularly to an arrangement around a speed meter drive gear mounted on an output shaft of an automatic transmission for vehicles.
A conventional automatic transmission for vehicles is known in which a governor support, a governor valve and a speed meter drive gear are spline-connected with an output shaft serially rearward thereon (for example, in U.S. Pat. No. 3,165,946).
In such a type of the transmission, a parking gear is provided along outer periphery of the governor support. When a parking lever is actuated, a pawl which is operatively connected with the parking lever is brought into engagement with the parking gear to lock the output shaft.
In such a serial arrangement of the parking gear, the governor valve and the speed meter drive gear, however, a large thrust force may occur in an axial direction of the output shaft due to engagement of the pawl with the parking gear on actuation of the parking lever. This would, on the one hand, readily cause the body of the governor valve to be damaged, concavely recessed or deformed resulting in so called valve stick by the gear teeth of the speed meter drive gear in a conventional structure in which a contact area of the governor valve with the speed meter drive gear is small. On the other hand, this would result in shifting of the governor support along the axis of the output shaft together with the governor valve to cause oil leakage at the oil seal portion in the oil supply lines for the governor valve.